This may not be a permanent solution, but it helped me out of a jam. I've noticed that when EN syncs with my iPad, iPhone and iMac, it doesn't always get it right. When there are conflicts, EN will paste a copy of the conflict along with a time stamp at the bottom of my note. Switch back and forth enough times and I end up with a massive note. It's so large that I can't even highlight and delete portions of the note without EN crashing, let alone typing. I was able to copy the up-to-date portion of my note and paste it onto a new note. Then I deleted the old note and problem solved. Now I'm left wondering how many other over-inflated notes I have and how that is affecting EN's performance.